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INTRODUCTION
The Learjet 45 hydraulic power system includes the reservoir, pumps, manifolds, con-
trol and shutoff valves, and a brake accumulator. Transducers, pressure switches, and
fluid level switches provide inputs on the systems status to the IC-600’s for display on
the engine instrument/crew alerting system (EICAS), the multifunctional display (MFD),
the radio management units (RMUs) and on the ground service panel.
Two engine-driven pumps supply hydraulic
fluid (MIL-H-5606), pressurized to approxi-
mately 3,000 psi for operation of the landing
gear, flaps, spoilers/spoilerons, brakes and
thrust reversers.
A DC motor-driven auxiliary hydraulic pump
can power all hydraulic subsystems during
maintenance by opening the ground servicing
valve. The auxiliary pump can also provide
hydraulic power for brakes prior to engine
start. Should the main hydraulic system fail,
it can provide hydraulic pressure for the land-
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L E A R J E T 4 5
P I L O T T R A I N I N G M A N U A L
CHAPTER 13
HYDRAULIC POWER SYSTEMS
13-1
FOR TRAINING PURPOSES ONLY
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